// 默认不允许在任何表达式中使用不必要的括号
(0).toString();

const result = (() => {
  console.info('arrow function');
}) ? '1' : '2';

(/^a$/).test(result);

(0).toString();

({}.toString.call());

(function(){}) ? a() : b();

(/^a$/).test(x);

for (a of (b, c));

for (a of b);

for (a in b, c);

for (a in b);

class A {
  [x] = 1;
}

class B {
  x = y + z;
}